SP REPCON PVT. LTD.

DEMARC STRAS STRUCTURAL SYSTEMS in Association with

Post tensioning Works | Ground Anchoring Works | Soil Stabilization |Retrofitting Works

ABOUT US

DEMARC STRAS STRUCTRAL SYSTEMS, a dynamic construction technology house that provides multi disciplinary services in design,

engineering innovative construction technologies. Our quality oriented institution DSSS is established under companies ACT.

Right from the inception our committed top class team registered a tremendous record, establishing extraordinary achievements

through our dedication and expertise in the field of construction.

DEMARC STRAS STRUCTRAL SYSTEMS provides design, supply, and execution of post—pretension services and special civil engineering

jobs on turnkey basis. DEMARC STRAS Expert design team provides innovative solutions to large business buildings and Geo technical-earth

retaining structures. Demarc Stras proud to be associated on land mark infrastructure and engineering projects.

DEMARC STRAS STRUCTRAL SYSTEMS offer fantastic quality solutions to our clients within and outside the region through our dynamic

expansion plans, involving technical teams with high class professional excellence.

VISION

Our Vision is to offer the ultimate Quick construction solutions for Projects.

MISSION

Our Mission is to accelerate the progress of infrastructural advancements through our innovative construction technologies involving

the world class professionals of utmost dedication and unparallel quality touch.

"Excellence" IS THE HALL MARK OF DEMARC STRAS.

We provide house full spectrum design and engineering services in Buildings,, Ground anchoring systems, Pile Load Test, Heavy lifting,

and other special engineering projects.

Design Team

Our superior engineering solutions in both design and executions deduct the construction cost, shorten the work duration and increase

the capacity. Our expertise team comprises graduates/ post graduate engineers. Our hubs in Andhra, Telangana, Delhi working in a

wide share environment, Creating ultimate professional brilliance.

Execution Team

Through our expertise on site engineers, we leverage our local presence and global reach to support clients. Complex projects,

challenging conditions and critical time lines we have built our reputation in construction by repeatedly delivering success within these

stringent parameters.

POST TENSIONING SYSTEMS:Post tensioned slab system can be constructed using bonded tendon systems.

Bonded Post Tensioning Systems:

a. Develop Higher ultimate flexural strength

b. Does not depend up on the anchorage after grouting

c. Localized the effect of damage

d. Simple technique for demolishing or providing future opening in slab.

DEMARC STRAS STRUCTURAL SYSTEMS Multiple strand Post tensioning range from 4 to 12 strands. The Post tensioning such multiple systems enables structural deflection and cracks under service conditions kept under control. This

permits larger spans thinner concrete sections to be used. Additionally there can be indirect saving on reduced column walls and

vertical surfaces.

Multi strand - Flat duct - Bonded tendon systems: The multi strand flat duct systems is normally adapted for bonded

tendons. The strands are individually gripped in one flat anchor head

unit and transmits their pre stressing forces by mean of flat anchor

type anchor plat casting unit. The strands are contained in one flat

duct which is made of corrugated galvanized or non galvanized metal.

To ensure corrosion protection and to give adequate bond strength,

the tendons are filled with suitable cement grout mix after complete

stressing of the strands.

The same anchorage for stressing anchorage can be used as dead end

anchorage in which case the wedges ate pre seated in the anchor head

unit by applying nominal force to the strand using the stressing jack.

Dead end anchorage: A bulb anchorage can be used a dead end anchorage with simpler

solution and more cost effective. in this case each strand is formed

into a bulb shape by means of special bulb forming Jack.

Stressing data :

Stressing data Tendon type 305

3

SF 305

SF 305/206

405

4

SF 405

SF 405/306

744

595

63.5x20

505

5

SF 505

SF 505/406

930

744

76.5x20

206

2

SF 205

SF 305/206

558

446

63.5x20

306

3

SF 306

SF 405/306

837

470

63.5x20

406

4

SF 406

SF 505/406

1116

892

76.5x20

No. of strands

Anchor head type

Anchor casting type

558

446

63.5x20

Stressing force at 0.5U.T.S., KN

Stressing force at 0.5U.T.S., KN

Flat duct inside Dia

0.5” (12.7 mm) 0.6” (15.2 mm)

DEMARC STRAS STRUCTURAL SYSTEMS - POST TENSIONING SYSTEMMulti strand - Round Duct - Bonded Tendon Systems:

Anchorage Components:

Multi Stand Anchorage Type M with round duct

Spiral Reinforcement for Anchorage

Dead Anchorage :

Dead and Anchorage

The systems are commonly used in bridge construction as well as other Civil

Engineering Structures such as silo., water tank, Transfer beams etc.,. The

systems normally adapted for bonded tendons. The tendon consists of a bundle of

strand with a nominal diameter of 0.5” (12.7mm) or 0.6” (15.2mm). The no. of

strands per tendon can be from 4 strands up to 31 strands of diameter 0.5” or 22

strands of diameter 0.6”. The strands in the tendons are contained in one round

duct which is made of corrugated galvanized or non galvanized metal.

The same anchorage can be used as dead anchorage in which case the strands are

gripped by means of wedge and are secured by springs and covered with cap

fastened agaist anchor plate casting to prevent intrusion of cement slurry into the

anchorage.

Bulb anchorage can be efficiently used as dead end anchorage. In this case each

strand is formed into a bulb shape by means of spacial bulb forming jack.

1. Wedges 2. Anchor Head Type M 3. Anchor Plate

Casting Type M 4. Grout Inlet 5. Corrugated Metal

Round Duct 6. Anchorage Spiral Reinforcement

Type

Spiral out side dia.

Length

Dia.

Pitch

Number of Pitch

Type

Spiral out side Dia.

Length

Dia.

Pitch

Number of pitch

405

180

250

12

50

5

406

190

300

12

50

6

705

215

300

14

50

6

706

250

350

14

50

7

1205

280

350

16

50

7

1206

335

400

18

50

8

D

L

d

p

n

D

L

d

p

n

Stressing Anchorage Data - For 0.5” / 12.7 mm Dia.

Stressing Anchorage Data - For 0.6” / 15.2 mm Dia.

Stressing anchorage data Number of strands dai. 0.5” (12.7 mm)

Tendon type

Ultimate tensile force per tendon, KN

Stressing force at 0.8 UTS, KN

Duct ID, mm

Jack Type

4

405

747

595

45

CDC25

7

705

1302

1042

55

CDC25

12

1205

2232

1786

70

CDC200

Stressing anchorage data Number of strands dai. 0.6” (15.2 mm)

Tendon type

Ultimate tensile force per tendon, KN

Stressing force at 0.8 UTS, KN

Duct ID, mm

Jack Type

4

406

1116

893

50

CDC25

7

706

1953

1562

65

CDC25

12

1206

3348

2678

80

CDC200

DEMARC STRAS STRUCTURAL SYSTEMS - POST TENSIONING SLAB SYSTEMS - BUILDINGS

DEMARC STRAS STRUCTURAL SYSTEMS - post-tensioning systems provide a means of strengthening concrete in resisting tension. DEMARC STRAS STRUCTURAL SYSTEMS systems Apply a compressive force to the structure through the stressing of high strength steel strand with specialized anchorage assemblies. the flexibility of the strand is a major advantage, allowing it to be profiled through the concrete element, counteracting a portion of the applied loads to provide an exceptionally efficient structure.

Advantages of post tensioned slabs

1. Increased clear spans

2. Thinner slabs

3. Lighter structures

4. Reduced Cracking and deflections

5. Reduces storey height

6. Rapid construction

The advantages can result in significant savings in overall costs. There are also some situations where are the height of the building limited, in which the reduced storey height has allowed additional storeys to be constructed with in building envelope.The major difference between a normal RC slab and a PT slab from design point of view is the tendons are stressed prior to its service, pre-compression is induced in concrete which that since counteracts the tensile stresses resulting from external loading. Also, since the material strength of pre stressing steel is very high, the flexural, shear and torsional strengths are enhanced. Hence, the structural design of post-tensioned slab involves the selection of a suitable tendon profile in such a way that the forces due to external loading are counteracted to certain extent, reduce the stresses in concrete and enhance the section strength.

DEMARC STRAS STRUCTURAL SYSTEMS - Ground Anchors

DEMARC STRAS STRUCTURAL SYSTEMS Ground Anchors are the application of Post tensioning systems in Geo Technical engineering.

The anchors are available in both temporary and permanent applications. anchors are designed to meet the standards of BS 8081, IS 10270

and PTI recommendations for prestressed rock and soil anchors. P.C. strand for ground anchors are normally standard products and P.C.

bar for ground anchors are also available upon special request.

Scope of Services:

DEMARC STRAS STRUCTURAL SYSTEMS Provides complete ranges of services for ground anchor system including

Design an analysis of structure to determine Ground Anchor system.

Design of Ground Anchors.

Supply of Ground Anchor Components.

Drilling of bore holes for Ground Anchors.

Installation, grouting and testing of Ground Anchor systems.

1)

2)

3)

4)

5)

DEMARC STRAS STRUCTURAL SYSTEMS - Ground Anchors :

Analysis and design of PT slabs are done using ADAPT PT and ADAPT Builder software. ADAPT PT is based on Equivalent frame method and ADAPT Builder is based on finite Element Method.

Under ultimate limit state. the strength of all critical sections is checked to resist the forces and moments induced due to gravity loading. Additional reinforcement is provided to increase the resistance of weaker sections. In case of flat slabs, punching shear resistance is checked at all column locations. Either drops or special reinforcement can be provided to increase the punching shear resistance.

Stresses, deflections and crack with are checked under limit state of serviceability against allowable values adopted by the respective code of practice. If exceeded, additional reinforcement shall be provided.

A layout of slab with details of tendon spacing and profile heights is provided. Elongation and jacking force for tendons are calculated.

Services

1. Project feasibility study for post tension application.

2. Preliminary design and cost estimation.

3. Final Design and shop Drawings.

4. Complete supply installation of post tensioning system.

DEMARC STRAS STRUCTURAL SYSTEMS

Offers two types of SB Ground Anchors as follows depend up on the Service life (SL).

Ground Anchor Parts:

1. Temporary Systems - SL < 24 Months

2. Permanent Systems - SL > 24 Months

Eliminating Fatigue stress

Eliminate Uplift

Negligible bond stress relief

Corrosion protection

1)

2)

3)

4)

Soil nailing

Rock Nailing

Inclined Ground Anchors

Vertical Ground Anchors

Passive Anchors

1)

2)

3)

4)

5)

Typical Applications : Benefits of DEMARC STRAS STRUCTURAL SYSTEMS - Ground Anchors :

Anchor head (H): Anchor head holding the Tendon under

tension and Transmitting the force in to The structure.

Fixed length (Lf): The length of the tendon over which the

force is transmitted in to the ground through the bond

between the pre stressing steel, the grout and the soil. It is

also called as the Bond Length.

Free Length (Lfr): The length of the tendon over which the

tendon can elastically elongate and is therefore also called

the un bonded length. To guarantee a free elongation this

length should not be smaller than 5 m.

Branch Office :D.No. 8-70, Eluru-1, West Godavari (Dist) Andhra Pradesh.

Branch Office : Flat No. 305, Vardhaman Jaypee Plaza, Plot No.6, Sector 4 Dwarka, New Delhi.

Contact : 040-27201200, Mobile : +91-9133302840 / 41, 011-25074587, 9654269665E-mail : varada@demarcstras.com

www.demarcstras.com

Corporate Office : H.No:2-19-74/7, Kalyanpuri, Uppal, Hyderabad, Telangana.